Not Applicable.
Not Applicable.
1. Field of the Invention
The present invention relates generally to antennas, and more particularly, to portable telephone antennas that can be extended and retracted in response to manipulation of portions of the telephone.
2. Description of the Invention Background
Ever since Alexander Graham Bell uttered those famous words to his assistant, xe2x80x9cMr. Watson come here. I want you,xe2x80x9d communication has not been the same. Indeed, Mr. Bell would likely marvel at the advancements that have been made over the years since his invention of the telephone. In recent years, portable telephones have become widely used means of communications, particularly between parties who may be away from their home or office. Such telephones are commonly equipped with an antenna for receiving and transmitting communications via radio signals.
Earlier portable telephone designs typically comprised a hand held unit that included a microphone/transmitter, a keypad, a speaker and a liquid crystal display unit. Such units also included a retractable antenna that was slidably retractable into the unit when not in use. Such earlier units tended to be somewhat bulky and cumbersome to carry. Thus, lighter and more compact units were eventually developed. One such design is commonly referred to as a xe2x80x9cflip-openxe2x80x9d style telephone wherein the telephone comprises two portions that are pivotally interconnected. When not in use, the microphone or xe2x80x9cmouthpiecexe2x80x9d portion is pivoted to a closed position wherein it essentially covers and protects the keypad portion to which it is pivotally attached. To expose the mouthpiece and keypad so as to make or receive a call, the mouthpiece is pivoted to a position away from the keypad, thus exposing both portions for use. U.S. Pat. No. 5,542,106 to Krenz et al discloses an example of a flip-open style telephone.
Another compact portable telephone design is known as the xe2x80x9cslidexe2x80x9d style telephone. In this design, one portion of the telephone body slides, rather than rotates, away from the second body portion to expose the keypad. An example of this design is disclosed in United Kingdom Patent Application No. 2,223,850, filed Aug. 22, 1989.
Such portable telephones may utilize a variety of antenna designs. Many portable telephones employ an antenna that must be manually extended and retracted by the user. An example of this type of antenna is disclosed in U.S. Pat. No. 5,493,690 to Shimazaki. Such manually operated antennas have many disadvantages. For example, because the extension and retraction forces are applied manually, the antenna is susceptible to inadvertent damage from excessive force or twisting forces applied to the antenna. Furthermore, it is not uncommon for the user to forget to retract the antenna after use, which can further lead to antenna damage. Finally, when a manual antenna is utilized, there is nothing to prevent the user from using the telephone with the antenna in a retracted or partially retracted position, thereby impairing the performance of the telephone.
To solve some of the problems associated with extended antennas, some portable telephones employ an internal antenna. These antennas provide an attractive appearance and result in a compact telephone that is easy to store. Examples of such antennas are set forth in U.S. Pat. No. 5,574,772 to Scalisi et al. and U.S. Pat. No. 5,542,106 to Krenz et al. While such internal antennas solve the above-mentioned problems commonly associated with manually extendable and retractable antennas, the quality of the transmissions can suffer.
Consequently, portable telephones with antennas that extend and retract automatically have been proposed. For example, U.S. Pat. No. 5,497,506 to Takeyasu discloses an antenna moving mechanism that extends the antenna out of the telephone housing when the telephone is placed in the operational mode and retracts the antenna back into the housing when the telephone is placed in xe2x80x9cstandbyxe2x80x9d mode. However, in this design, a motor controls movement of the antenna. This mechanism necessarily causes a significant power drain on the telephone and adds to the expense of the unit.
In an effort to solve the problems associated with motor controlled antennas, other antennas have been designed which are controlled by purely mechanical means. For example, U.S. Pat. No. 5,576,719 to Gerszberg et al. discloses a mechanism for automatically extending and retracting a radio telephone antenna in a xe2x80x9cflip-openxe2x80x9d type portable telephone. The device is purely mechanical. In this design, an antenna channel and an attachment point are configured so that the act of opening the telephone mouthpiece causes a wire to be pushed into the lower end of the channel. The upper end of the wire is coupled to the lower end of a rod-type antenna plunger. Thus, when the mouthpiece is opened, the upward push imparted to the wire results in extending the antenna plunger from the channel. When the telephone is flipped closed, the downward pull exerted on the wire by closing the mouthpiece retracts the plunger into the channel. This design, however, is limited to use on xe2x80x9cflip-openxe2x80x9d style portable telephones only.
U.S. Pat. No. 5,166,695 to Chan et al. also discloses an antenna that extends and retracts automatically wherein the movement of the antenna is controlled by purely mechanical means. In this design there are two toothed wheels intermeshed together. The first wheel is secured to the xe2x80x9cflipxe2x80x9d portion of a xe2x80x9cflip-typexe2x80x9d portable telephone. As the bottom portion of the phone is opened, the first wheel rotates, thereby causing the second wheel to rotate. Rotation of the second wheel causes the antenna to rotate along screw paths into an extended position. When the phone is closed, the antenna rotates in the opposition direction into the retracted position. However, this design is also limited to use with a xe2x80x9cflip-openxe2x80x9d style phone. Also, the design requires the use of a multitude of small parts, thereby increasing the likelihood of failure due to breakage of any one of the small components.
Thus, there is a need for a portable telephone antenna that automatically extends when the user is about to receive or make a call and automatically retracts when the call is completed.
There is a further need for an automatically extending and retracting antenna that does not require electrical power for operation.
A need exists for automatically extending and retracting antenna designs that can be incorporated into xe2x80x9cflip-openxe2x80x9d and xe2x80x9cslidexe2x80x9d style portable telephones.
Yet another need exists for an automatically extending and retracting antenna design that is resistant to wear or breakage and requires minimal operating parts.
In accordance with one form of the present invention, there is provided an antenna system that utilizes mechanically actuated apparatus for automatically extending and retracting the antenna. The novel antenna system is particularly advantageous for use in both the xe2x80x9cflip-typexe2x80x9d and xe2x80x9cslidexe2x80x9d style portable radiotelephones. In one embodiment of the invention, the system comprises a first elongated slide track affixed to an antenna. The first slide track has means disposed thereon for engaging a wheel that is affixed to at least a portion of the first slide track. Interlocking means are provided on the wheel that cooperate with engaging means provided on the first slide track. Means are also provided to rotate the wheel. When the wheel is rotated, a linear movement is imparted to the slide track. Since the antenna is affixed to the slide track, the antenna is moved linearly. Thus, depending on the direction in which the wheel is rotated, the antenna is automatically extended or retracted.
Various means may be utilized to rotate the wheel. In one embodiment, an elongated guide rod is provided, wherein the wheel is disposed at an end of the guide rod. This design is particularly useful in a xe2x80x9cflip-typexe2x80x9d radiotelephone. In this type of telephone, the guide rod is disposed between a first portion and a second portion of the body or housing of the telephone, is attached to the second portion and pivotally connects the first portion to the second portion. Thus, when the second portion of the body is rotated away from the first portion, the guide rod is rotated. Rotation of the guide rod turns the wheel, thus imparting a linear movement to the first slide track. When the second portion of the telephone body is rotated away from the first portion to an xe2x80x9copen positionxe2x80x9d, the antenna is extended out of the body. When the second portion is rotated back towards to first portion to a xe2x80x9cclosed positionxe2x80x9d, the antenna is retracted into the body.
In another embodiment, the means for rotating the wheel comprises a second elongated slide track. The second slide track also has means disposed thereon for engaging a wheel that is affixed to at least a portion of the second slide track. In this design, the second slide track is disposed in an opposed relationship to the first slide track, such that the wheel is disposed between the two tracks. This design is particularly desirable in a xe2x80x9cslidexe2x80x9d style telephone. In this type of telephone, the second portion of the body is slid away from the first portion of the body. Since the second slide track is disposed within the second portion of the body, this sliding action imparts a rotational force to the wheel. The rotation of the wheel causes the first slide track to move linearly in a direction opposite to that of the second slide track. Thus, when the second portion of the body is moved away from the first portion to an xe2x80x9copen positionxe2x80x9d, the antenna is extended out of the body. Conversely, when the second portion is slid towards to the first portion, the antenna is retracted back into the body.
A guide tube may also be optionally provided. When utilized, the guide tube slidably supports at least a portion of the antenna, such that when the antenna is extended and retracted, the guide tube supports the antenna within the body.
The present invention utilizes few parts, all of which are readily and inexpensively available. Consumers demand compact, attractive, and durable portable radiotelephones. It is an object of the present invention to address those demands with an automatically extendable and retractable antenna that is operated by mechanical means.